Camshaft phasers are utilized within IC engines to adjust timing of an engine valve event to modify performance, efficiency and emissions. Hydraulically actuated camshaft phasers can be configured with a rotor and stator arrangement. The rotor can be attached to a camshaft and actuated hydraulically in clockwise or counterclockwise directions relative to the stator to achieve variable engine valve timing. Electric camshaft phasers can be configured with a gearbox and an electric motor to phase a camshaft to achieve variable engine valve timing.
Many different camshaft configurations are possible within an IC engine. Some camshaft configurations include an intake camshaft that only actuates intake valves, and an exhaust camshaft that only actuates exhaust valves; such camshaft configurations can often simplify efforts to independently phase the intake valve events separately from the exhaust valve events. Other camshaft configurations can utilize a single camshaft to actuate both intake and exhaust valves; however, a single camshaft configured with both intake and exhaust lobes proves difficult to provide independent phasing of the intake and exhaust valves. For single camshaft configurations, a concentric camshaft assembly can be implemented that utilizes an inner camshaft and an outer camshaft, each arranged with one of either exhaust lobes or intake lobes, with each of the camshafts having a designated camshaft phaser to vary the respective engine valve timing.
One known camshaft phaser arrangement for a concentric camshaft assembly includes a first and a second camshaft phaser that are stacked coaxially at an end of the concentric camshaft assembly. A solution is needed that facilitates connection of this camshaft phaser arrangement to the concentric camshaft assembly while torsionally or rotationally coupling the two camshaft phasers to a crankshaft of the IC engine.